[Fe (II) (bpy) (III) ] (二+) 在溶液中的超快的非adiabatic动态
Wojciech Gawelda1, Andrea Cannizzo, Van-Thai Pham
1Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, Faculté des Sciences de Base, ISIC-BSP, Lausanne, Switzerland.
Journal of the American Chemical Society
|June 15, 2007
概括
铁中的超快放松 (II-tris-bipyridine) 通过从单元到三元状态的快速系统间交叉 (ISC) 发生,其次是五元状态的群体. 这个过程独立于金属旋转轨道合.
科学领域:
- 摄影化学的使用.
- 超快速光谱法 超快速光谱法
- 协调化学 协调化学
背景情况:
- 铁 (II) 复合物 (如铁 (II) -三 (二) 胺) 在光化学中至关重要.
- 了解激发状态动态是设计新光活性材料的关键.
- 超快的过程控制着光化学反应的初始步骤.
研究的目的:
- 在激发后,描述水性铁的超快放松通路{II) -tris{bipyridine).
- 为了确定系统间交叉 (ISC) 和随后的放松的时间尺度.
- 研究旋转轨道相互作用在放松动态中的作用.
主要方法:
- 五秒光向上转换光谱学.
- 五秒秒短暂吸收 (TA) 光谱学.
- 单数值分解和TA数据的全球分析.
主要成果:
- 观察到一个非常短暂的单片金属到合体电荷转移 (1MLCT) 辐射 (<20 fs).
- 将系统间交叉 (ISC) 转化为三重金属到质电荷转移 (3MLCT) 状态的特征 (<150 fs).
- 确定了三个不同的时间尺度 (120 fs,960 fs,665 ps),对应于3MLCT衰变,五重奏状态人口和衰变.
结论:
- 高的ISC率独立于金属的旋转轨道常数,这表明一种涉及避免交叉的机制.
- 一个单元和三元潜在能量曲线之间的避免交叉的模型解释了观察到的ISC率.
- 能量消散发生得很快 (2000 cm-1/100 fs),并且符合费米金律.
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